Apparatus for making sheet glass



Jan. 22, 1935. r w. RUCH APPARATUS FOR MAKING SHEET GLASS Filed June 30, 1933 2 Sheets-Sheet 1 Jan. 22, 1935. v w U 1,988,572

APPARATUS FOR MAKING SHEET GLASS Filed June 50, 19:55 2 Sheets-Shei 2 INVENTGR Ohm/066M Patented Jan. 22, 1935 PATENT OFFICE APPARATUS FOR MAKING SHEET GLASS Walter Ruch, Henryetta, kla., assignor to Pittsburgh Plate Glass Company, a corporation of Pennsylvania.

Application June 30, 1933, Serial No. 678,433

2 Claims. (01. 49-17) ward, as indicated in Fig. 1, and engage the re- 9 The invention relates to apparatus for making glass of the Slingluff type in which a submerged draw bar is used beneath the line of draw to maintain the line of draw and provide a cooler layer of glass from which to draw the sheet.

Inthe use of this apparatus, there are accumulations of cooled glass at the ends of the draw bar which in time interfere with the production of the sheet, sothat the drawing operation must be discontinued and the bath brought to p'roper condition again by a reheating operation which eliminates the chilled glass around the ends of the draw bar. The object of the present invention is to provide means for correcting the condition involving the accumulation of chilled glass at the ends of the draw bar, so that the drawing operation may be continued indefinitely without reheating. One embodiment of the invention is illustrated in the accompanying drawings, wherein:

Figure l is a vertical transverse section through a drawing extension or forehearth equipped with the invention. Fig. 2 is a partial plan view. And Fig. 3 is a detail perspective view on an enlarged scale.

Referring to the drawings, 1 is a drawing extension or forehearth connected to a melting ta and having the side walls 2, 2; 3 is a draw bar of refractory material extending transversely of the forehearth beneath the line of draw of the sheet 4; 5 is the lower end of-a leer provided with pairs of rollers 6 engaging the sheet and serving to draw it up through the leer continuously; 7 is the driving mechanism for the rolls; and 8, 8 are a pair of metal shields at the sides of the sheet for preventing too free a circulation of air across the portion of the sheet lying below the leer.

The draw bar is held in submerged position by 40 meansof a pair of blocks 9, 9 of refractory material, such as clay or mullite, whose construction is more clearly shown in Fig. 3. As indicated in this figure, each block is provided with a central recess 10 and a pair of combustion pockets 11, 11 extending upward from the body portion of the block and provided with inlet openings 12, 12 on their rear sides. Heating means are provided for these pockets in the form of pairs of burners 13, 13 connected to pipes 14, 14, in which a mixture of gas and air is supplied. By this means, the blocks are maintained at a relatively high temperature. In order to hold the blocks in position, the levers 15, 15 are employed, whose inner ends are turned downcesses 10 lying between the combustion pockets. These levers are pivoted at 16, 16 to suitable supporting brackets 17, 17 mounted on the outer sides of the walls 2, 2. The outer ends of the levers are threaded and engaged by the screws 18, 18, whose lower ends engage the upper sides of the brackets 17, 17. By this means, the blocks 9, 9 and the draw bar may be positioned at any desired level.

The blocks 9, 9 are maintained at a relatively high temperature by means of the gas burners 13, 13 so that the glass above the ends of the draw bar and opposite the edges of the sheet is maintained at a temperature which is much higher than would be the case if the blocks 9, 9 were not heated. As a result, an accumulation of cold glass is avoided so that the drawing operation may be continued indefinitely without interrupting the operation to remelt the glass as has heretofore been necessary. Such remelting operation is ordinarily accomplished by covering over the top of the forehearth and by supplying I gas through suitablevburners for combustion between the cover and the surface of the glass.

What I claim is: 1

1. In combination in glass drawing apparatus including a drawing extension, a draw bar extending transversely thereof, and means for drawing a glass sheet continuously from the molten glass lying above the draw bar, refractory blocks at the ends of the draw bar for holding it submerged in the glass, each of said blocks comprising a body portion engaging the draw bar and provided in its upper portion with a pair of heating chambers spaced apart and projecting inward of the body portion, means engaging the blocks between the chambers for holding them down, and gas burners supplying gas for tegral heating pockets at its upper end spaced apart and lying inward of the body portion, said pockets opening outwardly, means for engaging the blocks intermediate the pocketsfor holding the blocks down, and gas burners directed into the pockets for heating them. I

WALTER RUCH. 

